The present invention relates to an electronically controlled power saving, power supply system for fluorescent tubes.
More particularly, the present invention relates to a system which drives fluorescent tubes with a much higher efficiency than a traditional setup would, the comprehensive protective features of the circuit enabling the designer to design ballasts with protection against over voltages, removed tubes and over-currents. It is also possible to enhance the circuit by employing a thermal cutout as well.
The following disclosure describes an electronic driver for fluorescent tubes, better known as an xe2x80x9cElectronic Ballastxe2x80x9d.
It is known that hot cathode fluorescent tubes require an inductor, better known as choke, to limit the current and voltage to the tube from the incoming mains voltage. This setup also requires a switching element, better known as starter, to give the initial strike till the cathodes become warm. These starters have a relatively short life and give the annoying prolonged flashing during the starting phase.
The traditional setup arrangement produces another problem, which is somewhat more annoying or rather dangerous. When the tube is supplied from a 50 Hz source, this produces a 100 Hz flicker which is hardly noticed but in the presence of rotating machinery, becomes very hazardous since the machinery might seem to be stationary while rotating. This effect is better known as the xe2x80x9cStroboscopic Effectxe2x80x9d. Much has been done to try to solve the various problems, but others always arise.
The electronic driver system (electronic ballast) according to the present invention tends to solve practically all the problems of the prior art.
The characteristics of the device according to the invention will be stated in the characterizing part of the attached claims.